Aluminum soap of iso-octoic acids



tates ALUMINUM SOAP OF ISO-OCTOIC ACIDS No Drawing. Application November 20, 1952, Serial No. 321,747

5 Claims. (Cl. 260-448) (Granted under Title 35, U. S. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to aluminum soap of mixed isooctoic acids. More particularly, it relates to the aluminum di-acid soap of mixed iso-octoic acids. These soaps have a multitude of uses and have particularly good utility as thickening agents for liquid hydrocarbons. Thus, when these soaps are mixed with hydrocarbon fuels such as motor gasoline, they serve to produce the jellied gasoline used in flamethrowers and fire bombs.

The mixed iso-octoic acids from which these soaps are made are obtained by the oxidation of iso-octyl alcohols, the latter in turn being produced from mixed heptenes by an oxo process reaction. The acids are largely 5, 6 and 7 carbon atoms in length with resulting 3, 2 and 1 methyl group substituents on the carbon chain respectively. The 6 and 7 carbon atom chains are usually present in the greater proportion.

A disclosure of the 0x0 process for preparing oxidation products from olefins appears in U. S. Patent 2,553,364.

The aluminum di-acid soap is produced by reacting an aqueous sodium soap solution of the acid containing approximately 50% excess caustic, with an aqueous solution of an inorganic aluminum salt such as aluminum sulfate. The resulting insoluble hydroxy aluminum soap is filtered and washed free of by-product salts and dried.

The dried granular soap when added to liquid hydrocarbons create visco-elastic gels, the consistencies of which will vary with the concentration of thickening agent employed.

Example Dissolve 43 grams of C. P. sodium hydroxide in 850 ml. of water. Add 100 grams of mixed iso-octoic acids (neutral equivalent=143.5) and cool to room tempera ture by stirring. Slowly add 342 ml. of aluminum sulfate solution containing 137 grams of A12(SO4)318H2O, (iron free), in a fine stream with good agitation to precipitate the aluminum soap. The aluminum soap is filtered and washed free of sulfate ion as indicated by barium chloride test solution. The soap is first dried by exposure to room atmosphere on an open tray, and final drying is accomplished over phosphorous pentoxide in a desiccator.

Equations: The aluminum di-acid soap is precipitated in accordance with the following simplified equations.

Some mono-acid soap may precipitate concurrently in accordance with the following equation:

atent Because of hydrolysis the iii-acid soap'AlRz does not form, and acid in excess of that required remains as such adsorbed on the di-acid soap as indicated in the following equation:

Example Ten grams of aluminum soap was added to 240 grams of gasoline or mixed hydrocarbon test solvent. As the soap particles swell the vortex will close around the stirrer shaft. After aging from 4 to 24 hours the resulting 4% gel will have a consistency suitable for use as a fire bomb fuel or mechanized flamethrower fuel. Thickened fuels of lower consistency suitable for use in the portable flamethrower can be prepared in a similar manner at a concentration of 1.8 to 2.0%.

The use of aluminum soaps of long chain acids such as coconut oil acids and other vegetable oil acids as thickener for liquid hydrocarbon fuels, is well known. The mixed iso-octoic acids of the present invention are believed to be new in the art and have several advantages over those of the longer chain fatty acids.

It is shown, for instance, that lower concentrations of the soap are required to produce fuels of equivalent consistency, and gelation of hydrocarbons can be accomplished at lower temperatures without use of a peptizing agent. This makes the soaps of the present invention more efiective per unit of weight than the older aluminum soaps and are more readily used in the field. They also have improved moisture resistance over that of the prior art soaps and accordingly result in more reproducible fuels. Finally, the availability of the iso-octoic acids is much greater than that of vegetable oil acids since they can be produced in large quantities from the mixed heptenes available in petroleum refining.

It is understood that the invention is not limited to the specific example given since the salts may be produced by any of the processes which are well known in the art.

I claim:

1. Aluminum mono and di-acid soaps, of mixed isooctoic acids.

2. An aluminum di-acid soap of mixed iso-octoic acids.

3. Aluminum mono and di-acid soaps of mixed isooctoic acids wherein the acids are principally methyl heptoic, dimethyl hexoic, and trimethyl pentoic.

4. Aluminum mono and di-acid soaps, of mixed iso octoic acids wherein the acids are principally methyl heptoic and dimethyl hexoic.

5. The process which comprises reacting a mixture of iso-octoic acids, comprising principally mono, diand tri-methyl substituted heptoic, hexoic and pentoic acids respectively, with approximately 50% excess sodium hydroxide, adding to the solution an excess of aluminum sulfate to precipitate aluminum mono and di-acid soaps of iso-octoic acids, washing the resulting insoluble hydroxy aluminum soap free of sulfate ion anddrying the aluminum soap.

(References on following page) References Cited in the file of this patent UNITED STATES PATENTS Minich Dec. 11, 1945 Gebhart et a1 Mar. 11, 1947 Hunn. Jan. 15, 1952 4 Ndwak et a1. Jan. 29, 1952 Hunn Nov. 18, 1952 Smith et a1. Jan. 13, 1953 Allison et a1. Feb. 10, 1953 Mason Aug. 11, 1953 

1. ALUMINUM MONO AND DI-ACID SOAPS, OF MIXED ISOOCTOIC ACIDS. 